code: def start_call(self, info, headers):
      print("Starting new call:", info)
      if TRACE_HEADER in headers:
          trace_id = headers[TRACE_HEADER][0]
          print("Found trace header with value:", trace_id)
          TraceContext.set_trace_id(trace_id)
      return TracingServerMiddleware(TraceContext.current_trace_id())
  
imports: import argparse
  import sys
  import threading
  import uuid
  import pyarrow
  import pyarrow.flight
label_desc: Use image node_id 1 for calling the TracingServerMiddlewareFactory obj's underlying member method code with example usage: obj.start_call(info, headers) and returns: TracingServerMiddleware